Flocculants can be divided into inorganic flocculants and organic flocculants according to their chemical composition. Among them, inorganic flocculants include inorganic flocculants and inorganic macromolecule flocculants; organic flocculants include synthetic organic macromolecule flocculants, natural organic macromolecule flocculants and microbial flocculants.

　　Application of flocculants

　　1. Urban Sewage

　　The removal rate of COD and BOD in municipal sewage can reach 100% by treating domestic sewage with flocculating and degrading efficient mixed bacteria separated from municipal sewage.

　　2. Building Material Wastewater

　　The former mainly contains more clay particles, while the latter contains not only clay particles, but also a considerable amount of glaze medicines. Five minutes after adding NOC-1, the turbidity of embryo wastewater decreased from 1.4 to 0.043; the turbidity of glaze wastewater decreased from 17.2 to 0.35; the turbidity removal rates were 96.6% and 97.9%, respectively. The almost transparent supernatant was treated with flocculant produced by Rhodococcus erythropinus, and the treated supernatant was almost transparent.

　　3. Other Applications

　　Microbial flocculants are gradually used in food wastewater treatment due to their safety and non-toxicity, and satisfactory results have been achieved. In addition, microbial flocculants can also be widely used in the treatment of municipal wastewater, hospital wastewater, petrochemical wastewater, paper-making wastewater, pharmaceutical wastewater and other aspects.

　　Efficiency and residual amount are no longer polluted twice, which is an important direction for the future research and development of flocculants. Safe, non-toxic and efficient microbial flocculants have a tendency to replace traditional flocculants.